Modern vehicles are equipped with many electronic devices for passengers' convenience. These electronic devices include a navigation system, a hands-free mobile phone system, and so forth, as well as conventional electronic devices such as a radio and an air conditioner.
The conventional in-vehicle electronic devices provide a user interface through assigned buttons, and the use of a touch screen has been widespread in recent years. Passengers can manipulate these devices by directly touching them with their hands. However, such an operation based on passenger's eye sight and hand motion may hinder safe driving. Hence, there is a need to develop a user interface technology which does not hinder driving yet offers users convenience.
In order to solve this problem, an ultrasonic sensor was conventionally used to recognize hand's position and/or motion by distance and speed detection.
Moreover, the presence or absence of the hand and/or the position of the hand have been detected indirectly by interrupting an infrared beam with the hand or detecting a reflected signal.
A hand approaching within a close distance to an electronic device has been detected by electrically recognizing the proximity of the hand by an electrostatic capacitance sensor.
The technology for gesture recognition using the conductivity of a human body has been recently disclosed, which recognizes gestures by transmitting and receiving radio waves like an antenna.
However, the conventional method using the electrostatic capacitance sensor provides one-dimensional information only, such as distance, and can recognize some motions regardless of hand posture even if a plurality of sensors are used.
Also, even when using a 2D camera, such as a webcam, only a two-dimensional image seen by the camera is manipulated, thus making it difficult to measure the motion facing the camera.
The above information disclosed is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.